Originally you said: the Stern Review came out with quite non-scary estimates (“even after its shenanigans with the discount rates”). Now you’re saying: the Stern Review came out with really scary estimates but that’s OK because it fudged things, e.g. by using too-low discount rates.
The first, if it had been true, would have been good evidence against my statement that more or less all climate scientists say the consequences of business-as-usual would be pretty bad.
The second may be true (I haven’t looked closely enough to have a confident opinion) but even if true doesn’t give us good evidence that climate scientists don’t think the consequences will be bad. (It might indicate that they don’t think it’ll be so bad, else why not present their true reasons?. Or it might indicate that they’re so convinced it’ll be really bad that they’re prepared to fudge things to get the point across. Or it might be anywhere in between.)
Now you’re saying: the Stern Review came out with really scary estimates
No, not quite. The actual estimates from the Stern Review are non-scary. Indeed, non-scary to the degree that the authors felt the need to add some scary handwaving. But handwaving is not estimates.
doesn’t give us good evidence that climate scientists don’t think the consequences will be bad
Climate scientists are not domain experts in forecasting the effect of environmental change on human society.
5-6 degrees of temperature rise is scary. Economic loss equivalent to permanent 5-20% loss of global GDP is scary.
If you personally happen to be unscared by those figures, whether because you don’t believe them or because they’re about the fairly far future and your own discount rate is relatively high, fair enough. In that case we simply have a disagreement about what constitutes scariness.
scary handwaving
One difficulty here is that many of the things we may reasonably care about are not readily quantified; and any description of unquantified or barely-with-difficulty-quantified things can be dismissed as handwaving.
(But some of those things have less-handwavy more-quantified counterparts in the Report itself: e.g., tens to hundreds of millions of people displaced from their homes by the middle of the century because of flooding, sea level rise, and drought; 15%-40% of land plant and animal species extinct if temperatures rise a further 2degC. Again, how scary you think those things are depends on how much you care about the future, how much you care about people far away, how much you care about biodiversity, etc., and maybe we differ on some or all of them. I find them quite scary. Note that “how scary is this?” is a separate question from “will it actually happen?” and we’re discussing the former.)
Climate scientists are not domain experts in forecasting the effect of environmental change on human society.
I never claimed they are. I said only that climate scientists’ forecasts for the consequences of anthropogenic global warming are consistently at least “pretty bad”. (They are, of course, experts in forecasting what the environmental change is likely to be, which is an important part of the task of forecasting what its consequences will be.)
In that case we simply have a disagreement about what constitutes scariness.
We probably do. In this context, “scariness” mean willingness to spend resources now for expected mitigation of potential issues in the future. My willingness is lower than the current mainstream opinion and much lower than that of environmentalists.
many of the things we may reasonably care about are not readily quantified; and any description of unquantified or barely-with-difficulty-quantified things can be dismissed as handwaving.
Handwaving is not just lack of quantification, handwaving is asserting things without adequate support.
For example, I count the phrase “including a wider range of risks and impacts could increase this to 20% of GDP or more” as pure handwaving even though it includes a number.
how scary you think those things are depends on how much you care about the future
I don’t think we’re talking about “caring” in conventional sense. As I mentioned above, this is really about pricing of future risks with an overlay of generational transfer issues.
Just to be clear: The issue here AIUI is whether the Stern Report’s predictions, if correct, are scary. If we’re on the same page here, you’re saying that the prospect of a permanent loss of 5% or more of world GDP, of millions of extra deaths, and of tens to hundreds of people displaced from their homes, does not seem to you enough to justify the cost of the sort of mitigation the Stern Report proposes. Is that right?
If so: OK, fair enough; I’m not going to try to adjust your values. But I suggest that it’s probably quite unusual to regard those prospective harms as “quite non-scary”, as not “probably quite bad”.
pure handwaving
I think it’s actually somewhat impure handwaving because in the body of the Report there is a little explanation. But that explanation is itself fairly handwavy and in particular it’s not at all clear where the figure of 20% comes from.
pricing of future risks with an overlay of generational transfer issues
That seems to me like just one way of expressing “caring about the future”. In particular, using “caring” that way seems almost exactly as reasonable as using “scary” in the closely-related way you say you’re using it.
Not exactly—I don’t believe the “millions of extra deaths” projections and I strongly suspect that if I were to dig into the data, I would find the 5% GDP loss to be a shaky number.
In general, my position is that the best way to deal with uncertain threats in the future is to make sure future people are wealthy and technologically advanced. As an analogy, it would have been very unwise of, say, Europe in the XVIII century to suppress the industrialization because of concerns over deforestation, smog, and mines’ tailings.
This is irrelevant to the question we were actually addressing, namely how scary the predictions are. You made, in case you’ve forgotten, the following claim:
I would like to draw your attention to the Stern Review which came out with quite non-scary estimates for the consequences of the global warming even after its shenanigans with the discount rates.
but since then you have modified that by saying
that the SR’s NPV estimates of future harm are wrong because they should have discounted the future more steeply
that a lot of their predictions should be ignored because they are “handwaving”
that some of the more alarming other ones should be ignored because you don’t believe them
that the appropriate measure of scariness is your willingness to pay to make the scary thing go away.
At which point, it seems to me, you have completely abandoned the original statement that the Stern Review made non-scary predictions, and what we’re left with is that if we take only those parts of the Stern Review that you agree with and discount the future much more steeply than they do then you don’t find that considering what’s left makes you want to pay a lot of money to address the issue.
Or, to put it slightly differently, what we’re left with is: “Lumifer doesn’t think we should take drastic action to address possible negative future consequences of climate change”.
Well, fair enough. You’re a smart chap and no doubt your opinions are worth listening to. But this no longer has anything to do with the original issue, namely the extent to which climate scientists agree or disagree about climate change.
This is irrelevant to the question we were actually addressing, namely how scary the predictions are.
Let me, then, make the usual disclaimers which I thought were implicitly understood. I speak for myself, do not speak for anyone else, and when I discuss e.g. “how scary the predictions are”, I am talking about my perceptions, not about the reaction of an average (wo)man on the street.
Here I distinguish between what I think the Review actually says and what how it is presented. In my opinion, what the Stern Review says is not scary. It is presented as scary, of course, because that was the whole point of writing the Review. In fact, the shenanigans (e.g. discussed in the Wikipedia article) deemed necessary to produce the required degree of scariness reinforce my perception that the Review has major difficulties in creating a sufficiently fearful picture and contribute to my belief that what it actually found is non-scary.
the best way to deal with uncertain threats in the future is to make sure future people are wealthy and technologically advanced
The difficulty I have with applying that principle here is: which people? As the Stern Report says, the harms currently expected to result from climate change will fall overwhelmingly on the world’s poorest people. Ensuring that the inhabitants of the US and northwestern Europe are wealthy and technologically advanced will be very nice for us, but I’m not sure the people whose land becomes uninhabitable will (or should) consider that a great tradeoff.
The difficulty I have with applying that principle here is: which people?
I don’t understand your difficulty. The answer is: all and any.
This is similar to an observation that having a well-functioning immune system is the best way to deal with colds and other minor infections. The question “which people should have a well-functioning immune system?” makes no sense to me.
If indeed the answer is “all and any”, then the broad consensus that climate change under BAU scenarios will displace 50 million people in Bangladesh by the end of the century—turning vast numbers of prosperous farmers into penniless refugees—is a strong cause for action.
Originally you said: the Stern Review came out with quite non-scary estimates (“even after its shenanigans with the discount rates”). Now you’re saying: the Stern Review came out with really scary estimates but that’s OK because it fudged things, e.g. by using too-low discount rates.
The first, if it had been true, would have been good evidence against my statement that more or less all climate scientists say the consequences of business-as-usual would be pretty bad.
The second may be true (I haven’t looked closely enough to have a confident opinion) but even if true doesn’t give us good evidence that climate scientists don’t think the consequences will be bad. (It might indicate that they don’t think it’ll be so bad, else why not present their true reasons?. Or it might indicate that they’re so convinced it’ll be really bad that they’re prepared to fudge things to get the point across. Or it might be anywhere in between.)
No, not quite. The actual estimates from the Stern Review are non-scary. Indeed, non-scary to the degree that the authors felt the need to add some scary handwaving. But handwaving is not estimates.
Climate scientists are not domain experts in forecasting the effect of environmental change on human society.
5-6 degrees of temperature rise is scary. Economic loss equivalent to permanent 5-20% loss of global GDP is scary.
If you personally happen to be unscared by those figures, whether because you don’t believe them or because they’re about the fairly far future and your own discount rate is relatively high, fair enough. In that case we simply have a disagreement about what constitutes scariness.
One difficulty here is that many of the things we may reasonably care about are not readily quantified; and any description of unquantified or barely-with-difficulty-quantified things can be dismissed as handwaving.
(But some of those things have less-handwavy more-quantified counterparts in the Report itself: e.g., tens to hundreds of millions of people displaced from their homes by the middle of the century because of flooding, sea level rise, and drought; 15%-40% of land plant and animal species extinct if temperatures rise a further 2degC. Again, how scary you think those things are depends on how much you care about the future, how much you care about people far away, how much you care about biodiversity, etc., and maybe we differ on some or all of them. I find them quite scary. Note that “how scary is this?” is a separate question from “will it actually happen?” and we’re discussing the former.)
I never claimed they are. I said only that climate scientists’ forecasts for the consequences of anthropogenic global warming are consistently at least “pretty bad”. (They are, of course, experts in forecasting what the environmental change is likely to be, which is an important part of the task of forecasting what its consequences will be.)
We probably do. In this context, “scariness” mean willingness to spend resources now for expected mitigation of potential issues in the future. My willingness is lower than the current mainstream opinion and much lower than that of environmentalists.
Handwaving is not just lack of quantification, handwaving is asserting things without adequate support.
For example, I count the phrase “including a wider range of risks and impacts could increase this to 20% of GDP or more” as pure handwaving even though it includes a number.
I don’t think we’re talking about “caring” in conventional sense. As I mentioned above, this is really about pricing of future risks with an overlay of generational transfer issues.
Just to be clear: The issue here AIUI is whether the Stern Report’s predictions, if correct, are scary. If we’re on the same page here, you’re saying that the prospect of a permanent loss of 5% or more of world GDP, of millions of extra deaths, and of tens to hundreds of people displaced from their homes, does not seem to you enough to justify the cost of the sort of mitigation the Stern Report proposes. Is that right?
If so: OK, fair enough; I’m not going to try to adjust your values. But I suggest that it’s probably quite unusual to regard those prospective harms as “quite non-scary”, as not “probably quite bad”.
I think it’s actually somewhat impure handwaving because in the body of the Report there is a little explanation. But that explanation is itself fairly handwavy and in particular it’s not at all clear where the figure of 20% comes from.
That seems to me like just one way of expressing “caring about the future”. In particular, using “caring” that way seems almost exactly as reasonable as using “scary” in the closely-related way you say you’re using it.
Not exactly—I don’t believe the “millions of extra deaths” projections and I strongly suspect that if I were to dig into the data, I would find the 5% GDP loss to be a shaky number.
In general, my position is that the best way to deal with uncertain threats in the future is to make sure future people are wealthy and technologically advanced. As an analogy, it would have been very unwise of, say, Europe in the XVIII century to suppress the industrialization because of concerns over deforestation, smog, and mines’ tailings.
This is irrelevant to the question we were actually addressing, namely how scary the predictions are. You made, in case you’ve forgotten, the following claim:
but since then you have modified that by saying
that the SR’s NPV estimates of future harm are wrong because they should have discounted the future more steeply
that a lot of their predictions should be ignored because they are “handwaving”
that some of the more alarming other ones should be ignored because you don’t believe them
that the appropriate measure of scariness is your willingness to pay to make the scary thing go away.
At which point, it seems to me, you have completely abandoned the original statement that the Stern Review made non-scary predictions, and what we’re left with is that if we take only those parts of the Stern Review that you agree with and discount the future much more steeply than they do then you don’t find that considering what’s left makes you want to pay a lot of money to address the issue.
Or, to put it slightly differently, what we’re left with is: “Lumifer doesn’t think we should take drastic action to address possible negative future consequences of climate change”.
Well, fair enough. You’re a smart chap and no doubt your opinions are worth listening to. But this no longer has anything to do with the original issue, namely the extent to which climate scientists agree or disagree about climate change.
Let me, then, make the usual disclaimers which I thought were implicitly understood. I speak for myself, do not speak for anyone else, and when I discuss e.g. “how scary the predictions are”, I am talking about my perceptions, not about the reaction of an average (wo)man on the street.
Here I distinguish between what I think the Review actually says and what how it is presented. In my opinion, what the Stern Review says is not scary. It is presented as scary, of course, because that was the whole point of writing the Review. In fact, the shenanigans (e.g. discussed in the Wikipedia article) deemed necessary to produce the required degree of scariness reinforce my perception that the Review has major difficulties in creating a sufficiently fearful picture and contribute to my belief that what it actually found is non-scary.
The difficulty I have with applying that principle here is: which people? As the Stern Report says, the harms currently expected to result from climate change will fall overwhelmingly on the world’s poorest people. Ensuring that the inhabitants of the US and northwestern Europe are wealthy and technologically advanced will be very nice for us, but I’m not sure the people whose land becomes uninhabitable will (or should) consider that a great tradeoff.
I don’t understand your difficulty. The answer is: all and any.
This is similar to an observation that having a well-functioning immune system is the best way to deal with colds and other minor infections. The question “which people should have a well-functioning immune system?” makes no sense to me.
If indeed the answer is “all and any”, then the broad consensus that climate change under BAU scenarios will displace 50 million people in Bangladesh by the end of the century—turning vast numbers of prosperous farmers into penniless refugees—is a strong cause for action.
The default way to ensure future people are wealthy and technologically advanced is to let those who are not die.